O'Neill, who was the Minutemen's top assistant under Sam Koch the past two years, has a 92-90 college head coaching record over 11 seasons. The 2014 campaign will be his 21st at the college level.
The West Springfield, Mass. native had previous head coaching stops at East Carolina (1999-2002) and Gettysburg College (2003-09). He came to UMass following a two-year stint at Bradley in which the Braves participated in the NCAA Tournament each season.
O'Neill graduated from Middlebury in 1991 and received his master's degree from Springfield College in 1993.
David Lindholm has been named the assistant coach and will work with the team's goalkeepers.
Lindholm spent three seasons as a head coach at Salisbury (Conn.) School and a year as the goalkeeping coach at Middlebury College from 2005-07.
At Middlebury, he mentored Brian Bush who earned NSCAA First Team All-America honors in 2007 with a 0.32 goals-against average and 13 shutouts as the Panthers won the NCAA Division III National Championship with a 18-2-2 record.
A native of North Andover, Mass. who attended the Brooks School, Lindholm has spent the past seven years working in the media relations departments for MLS clubs CD Chivas USA and the Colorado Rapids. He also worked with the goalkeepers on the Chivas U-18 and U-16 teams.
He graduated from Middlebury in 2005 with a bachelor's degree in American Studies.UMass returns 14 letterwinners and eight starters from last year's team that went 4-14-1 and returned to the Atlantic 10 Conference Tournament for the first time since 2008.